He also wanted to ‘help the brothers’ plan an attack against his employer.

The suspect, a 51-year-old German who had converted to Islam, was caught by another agent who was posing as a radical Islamist in an online chatroom.

Duesseldorf prosecutors said yesterday that the plot was caught before any significant damage could be done.

‘So far, there have been no reliable indications that the accused had already given security-relevant information to people from the violent Salafist scene,’ prosecutor Ralf Herrenbrueck said.

German Chancellor Angela Merkel speaking at the 60th anniversary of the founding of the service this week (Picture: Reuters)

The suspect, whose identity has not been released, is now in custody and has partially confessed to investigators, Herrenbrueck said.

He is under investigation on suspicion of preparing an act of violence against the state and of an attempted violation of state secrets regulations, among other charges.

The man has been described by German media as a former bank employee who was married with children. He started with the intelligence service in April and was tasked with the surveillance of Salafisi Muslims, who adhere to an ultra-conservative form of Islam, Herrenbrueck said.